This invention relates generally to rollers and more particularly to rollers which are used to apply a surface coating to a can and to rollers used in graphics, embossing, laminating and spreading. Prior to the present invention, an economical and practical quick-change or replaceable roller to achieve these functions is not believed to have existed.
Heretofore, users of rubber-covered rollers in varied processing operations found that it was necessary to remove a damaged or worn-out roller from the shaft of a manufacturing machine and send it to a remote location for re-covering. This process was time consuming and expensive as the old roller typically had to be re-covered and then the surface thereof ground down so as to provide a suitable outer surface. Furthermore, the necessity to remove the entire roller required that an inventory of the large and heavy rollers (e.g. 6-24 inches in diameter; 20.gtoreq.140 pounds in weight) be maintained so as to minimize the substantial down time in the manufacturing process.
Attempts have previously been made to solve these problems by providing a covered roller with a removable sleeve, as typified by U.S. Pat. No. 3,771,206 to Brown, but these attempts are understood to be both commercially and operationally unsuccessful. As in Brown, which discloses a roller utilizing a metal core having a removable outer sleeve secured thereto by both lugs with corresponding notches and clamp means, the removable sleeve and the metal core do not maintain a concentric relationship to each other since the sleeve does not maintain full peripheral contact with the metal core when in use and is less satisfactory in performance than expensive conventional covered rollers due to this lack of concentricity. Furthermore, the Brown patent discloses that the cardboard tube of the removable sleeve is placed on a mandrel where the elastomer is cast thereon and finish ground prior to removal from the mandrel. This is a relatively expensive operation and is not required to be performed on the readily replaceable sleeve of the roller of the present invention.